Making the Sole Molds

For anyone who still doubts that I not only design but actually machine the molds for our OESH La Vida’s, here you go.

After laboring over CAD/CAM programming files, setting up the jig, securing the mold forms, and deciding which endmills and feeds and speeds to use, I take a deep breath and click the “Go” button on the computer that operates the CNC milling machine. When all goes as programmed…the coolant comes on, the endmill centers itself where it’s supposed to, and the carving begins.

Because the milling machine is kind of loud, it’s in a separate room with all the other loud machines. The milling machine will whirl away on its own for hours, spitting out metal chips until it’s time for me to change the endmill. The first endmill is a “roughing” square endmill that cuts down to the depth that dictates the thickness of the sole. The next endmill is a ball endmill that defines the tread of the sole.

I can’t help but think of Michelangelo with the advantage of computer programming, powerful servo motors, and a shop vac to suck away the enormous piles of shavings.

The flex grooves, the treads, the curve in the arch of the foot are exactly how I design them. And the mold vents are in the precise position I need them to be. I’ve made these molds a million times it seems, trying different configurations to get the material to flow just the way I want it to flow to achieve greater compliance in one part of the sole compared to another. Finite element analysis can get the mold design only so far. From there, it takes making a set of molds, injecting them and testing the soles, which, because we have our own machinery, we can do, every day.